A pressure gauge is a device that measures the pressure of a gas or liquid within a system. It typically consists of a dial or digital display connected to a sensor that measures the pressure of the substance, and a mechanism for displaying the measured pressure. Pressure gauges are commonly used in a variety of applications, including in air compressors, boilers, and automotive and aircraft systems, to monitor and control the pressure of gases and liquids. They are also commonly used in industrial, scientific, and medical settings to measure and control the pressure of various substances.

Pressure gauges are instruments that are used to measure the pressure of a fluid or gas within a system. They work by measuring the force that the fluid or gas exerts on a surface, and displaying this measurement in a convenient and easily readable form, such as on a dial or digital display.

There are several different types of pressure gauges that can be used to measure a variety of different pressures, including:

Gauge pressure: This is the pressure above or below atmospheric pressure.
Absolute pressure: This is the total pressure of a fluid or gas, including atmospheric pressure.
Vacuum pressure: This is the pressure below atmospheric pressure.
Differential pressure: This is the difference in pressure between two points in a system.
Hydrostatic pressure: This is the pressure of a fluid at rest, caused by the weight of the fluid.
Stagnation pressure: This is the pressure of a fluid in a system that is not flowing.
Impact pressure: This is the pressure of a fluid when it is moving at a high velocity.
Dynamic pressure: This is the pressure of a fluid when it is flowing through a system.
Static pressure: This is the pressure of a fluid when it is at rest.

Pressure gauges can be used to measure the pressure of a variety of fluids and gases, including water, oil, air, and other gases. They are commonly used in a variety of applications, including automotive, industrial, and laboratory settings.

A pressure gauge works by measuring the pressure of a fluid or gas within a system and displaying this measurement in a convenient and easily readable form. There are several different types of pressure gauges, but most operate on the same basic principle.

The heart of a pressure gauge is a flexible diaphragm or Bourdon tube that is connected to the system being measured. When the fluid or gas in the system exerts pressure on the diaphragm or Bourdon tube, it causes it to deform. This deformation is transferred to a mechanical linkage, which in turn moves a pointer on a dial or displays a digital reading.

The movement of the pointer or digital reading is proportional to the pressure being measured. The scale on the dial or display is calibrated to show the pressure in a specific unit of measurement, such as pounds per square inch (psi), bar, or kilopascal (kPa).

There are several different types of pressure gauges that use different methods to measure pressure, including mechanical gauges, electronic gauges, and digital gauges. Some pressure gauges also include additional features, such as alarms or transmitters, to help monitor and control the pressure within a system.